Safety control for gas stoves



14, 1951 LADE ET AL 2,563,944

SAFETY CONTROL FOR GAS STOVES Filed Feb. 16, 1948 IN VEN TORS FREDERICK L-LADE ERNEST G. SILVERTON RNEY Patented Aug. 14. 1951 SAFETY CONTROL FOR GAS STOVES Frederick L. Lade and Ernest G. Silverton, Vancouver, British Columbia, Canada Application February 16, 1948, Serial No. 8,593

' 2 Claims. 1 I

Our invention relates to improvements in safety controls for gas stoves.

The object of the invention is to provide electrically operated means operable in response to failure of any gas burner or pilot light for such burner to shut off the main supply valve to the gas stove to which the device is fitted.

In gas stoves where pilot lights are'provided, it has occurred that a liquid from a pan has been spilled or has boiled over the pan onto the burner immediately below and said liquid has plugged many' of the gas burner' jets within the range of the pilot, preventing said pilot from igniting the burner with the result that gas continues to flow from the orifices unaiiected by the-over, flowing liquid and a dangerous explosion has followed, being set off by the pilot light or another lighted burner. With the device as now proposed, the gas is shut off almost immediately after the spilling had taken place and continued gas flow is prevented.

Referring to the drawings:

Figure 1 is a plan view of a gas plate showing the invention.

Figure 2 is a sectional view 2-2 of Figure 1.

Figure 3 is a detail sectional view of aswitch included in the gas ring circuits.

Figure 4 is a diagrammatic view showing the electrical circuit.

In the drawings like characters of reference indicate corresponding parts in each figure.

The numeral l indicates generally a gas plate having two gas ring burners 2 and 3 mounted therebelow with a pilot light burner 5 mounted between said gas ring burners to light them.

The gas ring burners 2 and 3 and the pilot light burner 5 are supplied with gas through branch pipes I from a gas supply pipe 8. The gas supply pipe 8 is fitted with a main valve It by which the gas supply may be shut off from the gas ring burners and the pilot light burner. The valve I0 is closed by a spring ll surrounding its stem l2 an rgis opened by a solenoid I4 connected to said ste'rn, the solenoid being connected to a source of electrical supply. Each of the gas ring burners is normally controlled by manually operated valves ll, each of which is provided with a crank I9, see detail in Figure 2. A control switch 21 is provided adjacent each valve I! and another control switch 22 is provided adjacent the pilot light 5. Each of the control switches 2| and 22 is fitted with contact posts 24, which are connected in series with the solenoid I l in a suitable circuit 25. A thermostat 26 is mounted taken on the line in appropriate proximity to each of the gas ring burners 2 and 3 to be expanded thereby and a thermostat 21 is provided adjacent the pilot light burner 5, which is also expanded thereby.

Each of the control switches 2| and 22 is mounted in a casing 29 having top and bottom walls 30 and 3| respectively, and slidably extending through the wall 30 is a rod 32 fitted at its inner end with an insulated contact 33 adapted to bridge the contact posts 24. The outer end of the rod 32 is attached to one of the thermostats 25 so that the heating of said thermostat will effect the closing movement of said contact 33. The control switches 2| are also provided with an arm 35 mounted as at 36, the inner portion of said arm being apertured to receive the end of a push rod 38 of one of the valves I! which extends irom the end of the crank l9 through the wall 30. Adjacent the end of the push rod 38 a collar 39 is provided and between said collar and the arm 35 is a coil spring 40 which is adapted to move said arm when the complementary valve I! is moved to open position. Intermediate the length of said arm 35 is a light leaf spring 4! which carries an insulated contact 43,'for the purpose of bridging the contact posts 24 and to keep said contacts bridged until the arm 35 has moved downwards a predetermined distance as indicated in dotted line in Figure 3.

Disposed within the casing 29 is a dash pot 45, or other suitable action delaying device, the dash pot being provided with a piston 46, piston rod 41 and cylinder head 48. A light coil spring 49 is fitted upon the piston rod 47 which abuts the cylinder head 48 and the piston 46 for the purpose of returning the piston to rest position and for exerting a lifting strain on the arm 35 to move it upwardly, as the push rod is moved upwardly by turning the valve l! to closed position. It will be obvious that when a valve [7 is closed as shown in Figure 1, the contact 43 is also bridging its contact posts 24.

In use, when neither gas ring burners nor pilot burners are in use none of the thermostats 26 and El are heated and consequently all the switch contacts 33 are out of contact with their contact posts 24 and the main gas supply valve It will be closed under the influence of the spring H. Also, assuming that the gas-valves ll to the gas ring burners 2 and 3 are closed, the dash pot spring 49 of each control switch 2i will compress the leaf springs 4| and cause the contact 43 to bridge the contact posts 23, thus leaving the circuit 25 closed except at the control switch 22, which is connected with the 3 thermostat 27 of the pilot light burner 5. On applying heat to the thermostat 21, said thermostat will expand to depress the contact 33 of the switch 22 to bridge the contact posts 24, thus completing the closing of the circuit 25 which will cause the solenoid M to be energized and open the valve In admitting gas to the pilot light burner 5, so that it may be lighted to ignite the gas ring burners 2 and 3. To light either of said gas ring burners 2 or 3 its valve I! is turned to open position, allowing gas to flow thereto and become ignited. After a predetermined interval, the adjacent thermostat 25 is expanded and the contact 33 connected therewith will bridge its contact posts 24 and by the time this contact is closed the dash pot 45 will allow the arm 35 to swing in a downward direction and disconnect the contact 43 from said contact posts. So long as the aforesaid burner is functioning properly, the circuit 25 will remain closed, but if the ring burner should be put out, such as from a pan boiling over'and spilling onto it the thermostat 26 will contract, removing its associated contact 33 from the contact posts, breaking the circuit 25 and allowing the main valve It] to close down. Obviously with the gas being shut off at said valve the pilot light 5 will go out too and its thermostat 21 will contract, causing a further break through the switch-22 in the circuit, thus eliminating allhazard of explosion or fire from thestove.

While the invention has been described as being applied to a-gas stove having a pilot light burner, it will function equally well on anygas ring burner or gas fire, in which case a switch 2| would be used for each gas burner and a solenoid controlled main valve would be used on the gas supply pipe.

What we claim as our invention is:

1. In a safety device for a gas stove having ring burners, manually operated valves therefor and a pilot burner, each ring burner and pilot burner having a thermostat adjacent thereto, said device comprising a self-closing valve for supplying gas to the burners and the pilot burner and an electriccircuit including a'solenoid to open the self-closing valve, a switch operated by the pilot burner thermostat which when heated closes, and a second switch normally closed and. operated to open position after a time delay incidental to the opening of the manually operated valve, and a third switch operated by said ring burner thermostat in response to the heat thereof, to closed position prior to opening of said second switch to thereby maintain said circuit closed.

2. In a safety device for a gas stove having ring burners, manually operated valves thereforand a pilot burner, each ring burner and pilot burner having a thermostat adjacent thereto, said device comprising a self-closing valve for supplyinggas' to the burners and the pilot burner and an electric circuit including a solenoid to open the self-clo sing valve, a switch operated by the pilot burner thermostat which when heated closes, and a second switch normally closed and operated to open position after a time delay incidental to the opening of the manually operated valve, and a third switch operated by said ring burner thermostat in response to the heat thereof, to closed position prior to opening of said'second switch to thereby maintain said circuit closed and means for retarding the opening of the circuit through said second switch until the manually operated valve is opened a predetermined distance.

- FREDERICK L. LADE.

ERNEST-G. SILVERTON.

REFERENCES CITED The iollowing references are of record in the file or this patent:

UNITED STATES PATENTS Number Name Date 961,904: Skillcorn June 21, 1910 1,635,104 Woods July 5, 1927 1,676,671 Schwartz July 10, 1928 1,870,007 Herbster Aug. 2, 1932 2,080,070 Wright et a1. May 11, 1937 2,095,813 Herbster Oct. 12, 1937 2,183,855 Mansky Dec. 19, 1939 

